|About this Abstract
||2016 TMS Annual Meeting & Exhibition
||Characterization of Minerals, Metals, and Materials
||LL-77: Microstructural Characterization of Boron-rich Boron Carbide by Transmission Electron Microscopy
||Kelvin Xie, Vlad Domnich, Jim McCauley, Rich Haber, Kevin J Hemker
|On-Site Speaker (Planned)
Boron carbide is an attractive engineering material due to its low density and super hardness, and recent efforts to enhance the ballistic performance of boron carbide have focused on control of stoichiometry, composition and crystallographic defects. Boron carbide has a wide solubility range extending from approximately 80-92 at.% boron. We investigated the effect of stoichiometry on the densification, microstructure and mechanical properties of hot-pressed boron carbide ceramics. Additional boron results in denser samples as compared to stoichiometric B4C. Microscopically the additional boron dissolves into the B4C powders during sintering, leading to boron-rich grains after consolidation. Detailed TEM and HREM observations point to the formation of extensive intragranular planar defects (e.g. stacking faults and twins) for boron-rich samples, but not in stoichiometric B4C or carbon-rich samples. The effect of boron content on the hardness and indentation fracture toughness will also be discussed.
||Planned: A print-only volume